Radio shielded spark plug lead



s 3939- I M. F. PETER$ ET AL 9 5 RADIO SHIELDED SPARK PLUG LEAD FiledJan. 10, 1958 34 L/fl INVENTORS 25 W W m/QM;

Patented July 1939 -UNI'TEDSTATESD PATENT OFFICE 2.104.591 namo SHIELDEDsraax PLUG LEAD Melville F. Peters, Beltsville, Md., and a. Harry Stone,Bound Brook, N. 5.

Application January 10, 1938, Serial No. 184,306

Claims. (cr es-14s) This invention relates to an improved structure ofradio shielded spark plug lead for internal combustion engines.

As is well known, a shielded ignition system for 5 an internalcombustion engine has comprised an are shaped structure embracing theengine shaft,

through which pass all the ignition conductors leading fromthe magnetoto the spark plugs. Such are shaped structure serves, especially in inconnection with radial engines such as commonly used on aeroplanes, toguide and support the conductors about the engine shaft and alsoconstitutes a radio shieldabout them, and is commonly known as amanifold. At suitable points 15 on the manifold, conduits and conductorsextend to the magneto-and also extending from the manifold at certainsuitable'points are spark plug leads, to the various spark plugs, eachof said spark plug leads comprising a. suitable conductor and a radioshielding conduit therefor.

The main-object of the presentinvention is to provide an eilicient andsimple construction of spark plug lead.

'I'he conductors of spark plug leads are often injured by heat of theengine or otherwise so as to require renewal.

It is a further object of the invention to provide a spark plug leadwhereof the conductor can be removed or replaced with minimum trouble,

delay and expense.

The renewal or replacement of a-radio shielded spark plug lead hasheretofore involved a joint permitting the disassembly of its conduitfrom the manifold. This detachability however involves the insecurity ofconnection of such structures and affords a joint at which water leakagemay occur. Moisture within the conduit cannot be tolerated for obviousreasons.

It is therefore a further object of the invention to provide a sparkplug lead wherein the conduit may be permanently connected with themanifold and the conductor nevertheless be removed or replaced.

' Other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawing which illustrates plug end of the lead ofFig. 1, the remainder being broken away; 7

Fig. 3 is an axial section to the same scale as Fig. 2 of the manifoldend of the spark plug lead, the remainder being broken away. 5

Referring to the drawing, the conductor-encasing longitudinallyarc-shaped manifold I of metal, has at suitable intervals outletopenings 2, one for each sparkplug. Each of such openings has a nipple 3integralwith the manifold and 10 surrounding the opening. Mounted in thenipple 3 is a contact support 4 of suitable insulation having a centralsocket like opening 5 in the bottom of which is the metal terminal plate6 for the manifold conductor 1 which extends through 18 the end of thesupport 4 and the contact plate 6 and has its end riveted or peened overtightly against the plate 6, the plate 6 and peened over and of theconductor constituting the terminal. The parts are so joined and fittedat the nipple go that a fluid tight barrier is formed between theconduit for the spark plug lead and the interior of the manifold. Theconductor I is connected through the manifold and suitable leads, withthe magneto as is well understood. Within the manifold the conductor 1has a suitable insulating covering 8.

The shielded spark plug lead comprises the metal tube 8 constituting theradio shielding con-' duit for the conductor I 0 from the manifold to 30the spark plug, such conductor being bare adjacent its ends butotherwise having an insulating covering Ii. At the manifold end of thelead the bare end .30 of the conductor has the metal washer 3i threadedupon it, the washer bearing against the end of the insulation H andsecured in position by bending over the end of the conductor andsoldering or not as may be desired. soldered to the washer 3| isa spiralmetal spring 32 adapted to press against and have flrm elec- 40 tricalcontact with the terminal of the conductor 7 when the conductor I0 is inoperative position in the lead.

a One end of the tube 9 is permanently and securely joined with thenipple 3 by abutting its 5 end against the nipple, placing a metal bandit" about'the nipple and tube to bridge the joint and securely, tightlyand fixedly welding or soldering the whole together. I

The other end of the tube 9 has a flange i3 59 engaged by a flange ll ofa nut i5 screw-threaded upon the end of the elbow l6, such nut servingto draw the ends of the tube 9 and "elbow IE tightly and firmlytogether, a gasket being interposedbetween the tube and elbow if'desired,

' to insure fluid tightness, This "elbow commonly so called, is thecurved portion of the metal shielding conduit connecting with the sparkplug.

The spark plug end of the elbow has screwed upon it the metal member I Ihaving the flange l8 engaged by the flange IS on the threaded nut 20adapted to be screwed onto the spark plug shield to secure the elbowtightly and securely thereto as is well understood.

Screwed into the member I! is a tubular mounting 2| of insulation intothe bore 22 of which extends the insulation covered conductor l0, andalso in the bore 22 is the metal contact washer 24 threaded on theconductor and bearing against the end of the insulation II. The washeris held in position by bending over the end of the conductor on theoutside and soldering or not as desired. Also in the bore 22 is the disk25 bearing at one side against the end of the conductor l and to the.other side is soldered one end of a metal spring 26 adapted to hear atits other end against the central electrode of the spark plug.

The spring thus acts to connect the conductor Ill with the electrode ofthe sparkplug and is of such dimensions and resilience as to tightlypress the conductor Ill, disk 25 and spark plug contact together so thatthere will be good and firm electrical connection between them. Theother end (that adjacent the manifold) of the conductor in bears throughthe spring 32 against the contact plate 6 or the riveted end of theconductor i so that firm electrical connection is established from theconductor 7 to the spark plug electrode.

If now it be desired to remove the conductor because of injury, or forany reason, the elbow" may be separated from the tube 9 by unscrewingthe nut l when the conductor being unsecured to the contacts at its endsmay be withdrawn from the tube and elbow by simply pullingit out, or theelbow may be separated from the spark plug shield by unscrewing the nut29 and then the conductor can be pulled out through the spark plug endof the elbow.

A new conductor may be inserted, where the elbow and tube 9 areseparated by pushing one end of the conductor endwise into the tubeuntil the spring at its manifold end is compressed and bears firmlyagainst the terminal of the manifold conductor and pushing the other endof the in-.

serted conductor into the elbow and securing the elbow in position whenthe spring 26 will be compressed and securely connect the conductor inwith the spark plug electrode. Preferably the conductor is solid ratherthan stranded but any type may be used having the desiredcharacteristics as indicated.

When the parts are disassembled at the nut 26 instead of at the nut l5,the new conductor may be'pushed endwise inwardly from the spark plug endof the elbow, through the elbow and conduit tube 9 so that its insertedend bears against the terminal contact of themaniiold conductor and theparts then assembled as described.

While the invention has been illustrated in what-is considered its bestapplication it may have other embodiments without departing irom itsspirit and is not therefore limited to the structures shown in thedrawing.

What we claim is:

1. In an engine ignition system, the combination with a'manifold havingan opening, of a radio shielding conduit permanently secured at one endto said manifold adjacent said opening, means at the other end of saidconduit for connecting it with the spark plug radio shield and providinga radio shielded passage from said conduit to said spark plug shield, aconductor in said manifold, a terminal for said conductor mountedadjacent said opening and a conductor in said conduit insulated from themetal thereof and adapted at one end to be connected with the electrodeof a spark plug and at the other end bearing against said terminal butbeing unsecured thereto against a Dull tending to withdraw saidconductor from said conduit.

2. In an engine ignition syste the combination with a manifold having anopening, of a radio shielded conduit permanently secured to saidmanifold adjacent said opening, a conductor in said manifold, terminalsfor said conductor adjacent said opening and a conductor in said conduitbearing against said terminal in conducting engagement therewith. andadapted to be connected and disconnected therefrom by the inser-, tionin and withdrawal of the last mentioned conductor from said conduit.

3. In an engine ignition system, the combination with a manifold havingan opening, of a radio shielding conduit permanently secured at one end.to said manifold adjacent said opening,

a radio shielding elbow at the other end of said conduit, means forconnecting said elbow with the spark plug radio shield, a conductor insaid manifold, a terminal for said conductor mounted adjacent saidopening and a conductor in said conduit insulated from the metal thereofand adapted at one end to be connected with the electrode of a sparkplug and at the other end bear-. ing against said terminal, but beingunsecured thereto against a pull tending to withdraw said conductor fromsaid conduit.

4. In an engine ignition system, the combination with a manifold havingan opening, of a radio shielding conduit permanently secured at oneendto said manifold adjacent said opening, means at the other end ofsaid conduit for connecting it with the spark plug radio shield andproviding a radio shielded passage from said conduit to said spark plugshield, a conductor in said manifold, a terminal for said conductormounted adjacent said opening and an insulated covered conductor in saidconduit and adapted at one end to be connected with the electrode of aspark plug and at the other end bearing against said terminal but beingunsecured thereto against a pull tending to withdraw said conductor fromsaid conduit.

5. In an engine ignition system, the combination with a manifold havingan opening, of a radio shielding conduit permanently secured at one endto said manifold adjacent said opening,

' electrode of a spark plug and at the other end bearing against saidterminal but being unsecured thereto against a pull tending to withdrawsaid conductor from said conduit, there being at the spark plug end ofthe conductor in the conduit a spring-pressed terminal against which thelast mentioned conductor detachably bears.

6. In an engine ignition system, the combination with a manifold havingan opening, of a conductor therein, a radio shielding conduitpermanently secured to said manifold adjacent said opening, a terminalfor the manifold conductor adjacent said opening and a conductor in saidconduit separate from but electrically connected with said terminal.

7. In an engine ignition system, the combination with a manifold havingan opening, of a conductor therein, a radio'shielding conduitpermanently secured to said manifold adjacent said opening, a terminalfor the manifold conductor adjacent said opening and a conductor in saidconduit detachably connected with said terminal and means forming afluid-tight barrier between said conduit and said manifold.

8. In an engine ignition system, the combination with a manifold havingan opening, of a conductor therein, a radio shielding conduitpermanently secured to said manifold adiacent.

said opening, a terminal for the manifold conductor adjacent said.opening and a conductor in said conduit detachably connected with saidterminal and means forming a fluid-tight barrier between said conduitand said manifold; the said terminal being mounted in said barrier.

9. In an engine ignition system, the combination with a manifold havingan opening, of a radio shielding conduit tly secured to said manifoldadjacent said opening. a conductor in said manifold, terminals for saidconductor adjacent said opening and a conductor in said conduit bearingagainst said terminal in conducting engagement therewith and adapted tobe connected and disconnected therefrom by the insertion in andwithdrawal of the last mentioned conductor from said conduit, the lastmentioned. conductor having at its end aspring secured to it andcompressed against said terminal.

10. In an engine ignition system, the combination with a manifold havingan opening, of a radio shielding conduit permanently secured to saidmanifold adjacent said opening, a conductor in said manifold, terminalsfor said conductor adjacent said opening'and a conductor in said conduitbearing against said terminal in conducting engagement therewith andadapted to be connected andrdisconnected therefrom by the insertion inand withdrawal of the last mentioned conductor from said conduit, thelast mentioned conductor having at its end a spring secured to it andcompressed against said terminal and a spring at the spark plug end ofthe conductor adapted to be compressed against a spark plug electrode.

MILVIILE I". PETERS. R. HARRY STONE.

